1. Field of the Invention
The present invention relates to an accumulator used for accumulation and buffer of a pressure liquid and, more particularly, to a bladder-type accumulator with sensor.
2. Description of the Prior Art
In a bladder-type accumulartor, if a liquid more than normal in quantity comes into a vessel body according to a fluctuation of liquid pressure, a bladder is capable of being compressed to exceed a threshold. If so, then the bladder is thrust partly into a clearance between the vessel body and a cover to failure. Thus, once the bladder is damaged, a gas leak may arise, and the accumulator is no more functional for accumulation and buffer of a pressure liquid.
Now, therefore, a bladder-type accumulator with sensor has been developed to solve such problem.
The bladder-type accumulator with sensor then comprises providing a rod projecting into the bladder axially on a cover of the vessel body, inserting the middle portion of an elastic bowl-like sensor slidably in the rod, providing a sliding rod on an outer periphery of the rod, linking one end of the sliding rod and an inside of the bowl-like sensor together, and providing a magnet for actuating a switch on the other end.
Then, the bladder transformed according to a change in liquid pressure pushes the elastic bowl-like sensor to slide the sensor and the sliding rod, and when the sliding rod shifts as far as a predetermined position, a switch is turned on to generate a signal.
Then, the following problems are inherent in the prior art bladder-type accumulator with sensor.
(1) Since the elastic bowl-like sensor slides as coming in contact directly with the rod, there arises a sliding friction.
Consequently, the sensor does not slide smoothly, and thus is prevented from transforming essentially or quickly to coordinate with a liquid pressure fluctuation.
(2) The elastic bowl-like sensor slides as coming in face contact with the bladder, therefore a sliding friction also arises here.
Consequently, a contact surface of the bladder and the elastic bowl-like sensor wears to failure, therefore it must be replaced as occasion demands.
That is, as the elastic bowl-like sensor is disposed within the bladder, a life of the bladder is shortened.
Further, when the elastic bowl-like sensor slides, not only a sliding friction against the rod but also a sliding friction against the bladder as mentioned above arises, therefore the sensor becomes hard still further to slide smoothly.
Thus, the pressure liquid becomes hard more and more to come smoothly into the accumulator, and a performance of the accumulator comes to deteriorate.